Tolerance ring

ABSTRACT

A tolerance ring including a sidewall having a first and a second opposite major surfaces spaced apart by a thickness, wherein the first major surface defines an inner diameter of the tolerance ring at a first location of the sidewall and an outer diameter of the tolerance ring at a second location of the sidewall. A method of forming a tolerance ring including providing a strip of material comprising a first, a second, a third, and a fourth edge, shaping the first edge of the strip toward the third edge, and shaping the second edge of the strip toward the fourth edge.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority from U.S. Provisional PatentApplication No. 62/044,752, filed Sep. 2, 2014, entitled “TOLERANCERING,” naming inventor Neil James, and said provisional application isincorporated by reference herein in its entirety for all purposes.

FIELD OF THE DISCLOSURE

The present disclosure relates to tolerance rings, and more particularlyto tolerance rings having folded portions.

RELATED ART

A tolerance ring may be disposed in a radial gap formed between an innercomponent, e.g., a shaft, and an outer component, e.g., a bore formed ina housing. The tolerance ring can act as a force limiter to permittorque transfer between the inner and outer components. The use of atolerance ring can accommodate variations in the diameter of the innerand outer components while maintaining interconnection therebetween.

Typically, a tolerance ring comprises a band of resilient material, e.g.a metal such as spring steel, the ends of which are brought towards oneanother to form an annular ring. Although tolerance rings typicallyinclude a strip of resilient material curved to form an annular ring, atolerance ring may also be manufactured as an annular band. Projectionsare usually stamped or rolled into the tolerance ring. The projectionscan span the radial gap between the inner and outer components andtransmit forces therebetween.

There continues to exist a need for tolerance rings having improvedforce loading characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in theaccompanying figures.

FIG. 1 includes a top perspective view of a tolerance ring in accordancewith an embodiment.

FIGS. 2A to 2E includes cross-sectional side elevation views ofalternate embodiments of a tolerance ring, as seen along Line A-A inFIG. 1.

FIG. 3 includes a cross-sectional side elevation view of a tolerancering in accordance with an embodiment, as seen along Line B-B in FIG. 1.

FIG. 4 includes a front elevation view of a strip of material inaccordance with an embodiment prior to shaping the tolerance ring.

FIGS. 5 and 6 include cross-sectional side elevation views of the stripof material in accordance with embodiments, as seen along Line C-C inFIG. 4, prior to and during shaping of the tolerance ring.

FIG. 7 includes a top perspective view of a tolerance ring in accordancewith an embodiment, as the circumferential ends are brought together.

FIG. 8 includes a top perspective view of a strip of material inaccordance with an alternate embodiment, during shaping of the tolerancering.

FIG. 9 includes a top perspective view of a tolerance ring preassemblyin accordance with an alternate embodiment, prior to shaping thecircumferential ends together.

FIG. 10 includes a cross-sectional side elevation view of the tolerancering in accordance with an embodiment.

FIG. 11 includes a cross-sectional side elevation view of an assemblyincluding an inner component, and outer component, and a tolerance ringin accordance with an embodiment.

Skilled artisans appreciate that elements in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the elements in the figures maybe exaggerated relative to other elements to help to improveunderstanding of embodiments of the invention.

DETAILED DESCRIPTION

The following description in combination with the figures is provided toassist in understanding the teachings disclosed herein. The followingdiscussion will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings. However, other embodiments can be usedbased on the teachings as disclosed in this application. Reference toranges

The terms “comprises,” “comprising,” “includes,” “including,” “has,”“having” or any other variation thereof, are intended to cover anon-exclusive inclusion. For example, a method, article, or apparatusthat comprises a list of features is not necessarily limited only tothose features but may include other features not expressly listed orinherent to such method, article, or apparatus. Further, unlessexpressly stated to the contrary, “or” refers to an inclusive-or and notto an exclusive-or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or notpresent), A is false (or not present) and B is true (or present), andboth A and B are true (or present).

Also, the use of “a” or “an” is employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one, at least one, or the singular as alsoincluding the plural, or vice versa, unless it is clear that it is meantotherwise. For example, when a single item is described herein, morethan one item may be used in place of a single item. Similarly, wheremore than one item is described herein, a single item may be substitutedfor that more than one item.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting. To theextent not described herein, many details regarding specific materialsand processing acts are conventional and may be found in textbooks andother sources within the tolerance ring arts.

A tolerance ring in accordance with one or more of the embodimentsdescribed herein can generally include a sidewall having a first and asecond opposite major surfaces spaced apart by a thickness. The firstmajor surface can define an inner diameter of the tolerance ring at afirst location of the sidewall and an outer diameter of the tolerancering at a second location of the sidewall. In an embodiment, the firstmajor surface can define a radially innermost surface of the tolerancering at the first location of the sidewall and a radially outermostsurface of the tolerance ring at a second location of the sidewall. Inan embodiment, a tangent to the first major surface at the secondlocation can be parallel to a central axis of the tolerance ring.

A tolerance ring in accordance with one or more of the embodimentsdescribed herein can generally include an axially formed multiple-wallconstruction along at least 25% of an axial length of the tolerancering.

Referring now to FIG. 1, a tolerance ring 2 can generally include asidewall 4 defining one or more folded portions 5. The sidewall 4 can begenerally annular, e.g., a ring, having a central axis 8. In anembodiment, the folded portion(s) 5 can be formed by shaping a portionof the sidewall 4. In a further embodiment, the folded portion(s) 5 canbe at least partially formed by shaping portions of the sidewall 4. Moreparticularly, as described in greater detail below, the foldedportion(s) 5 can be at least partially formed by folding an axial end ofthe sidewall 4 toward an opposite axial end of the sidewall 4.

In an embodiment, such as illustrated in FIG. 2A, at least one of thefolded portions 5 of the sidewall 4 can define at least one compressionfeature 6 having a spring effect, i.e., the folded portion 5 can allowfor absorption of a tolerance or misalignment between inner and outercomponents, e.g., between a shaft and a bore (FIG. 11). In anembodiment, the spring effect can be derived from the materialproperties of the sidewall 4, including the material properties of thefolded portions 5. In a particular embodiment, as discussed in greaterdetail below, the spring effect can be achieved by use of a sidewallmaterial having a high yield and/or elastic strength.

In other embodiments, such as, for example, as illustrated in FIGS. 2Bto 2D, at least one of the folded portions 5 of the tolerance ring 2 caninclude a projection 7. More particularly, the folded portion(s) 5 canfurther include one or more radially extending projections 7. Theprojections 7 can be stamped, punched, rolled, or otherwise shaped intothe sidewall 4 by a process recognizable in the art to skilled artisans.In these embodiments, tolerance can be absorbed by deformation of theprojections 7, e.g., plastic or elastic deformation, alone or incombination with the spring effect of the compression feature 6. In anembodiment, the radially innermost edges of the compression feature 6and the projection 7 can lie along a same plane. In another embodiment,the innermost radial edges can lie along different planes.

Referring particularly to FIG. 2B, in a certain embodiment, both of thefolded portions 5 can exhibit zero, or nominal, spring effect. Rather,projections 7 formed on each of the folded portions 5 can absorbtolerances and radial forces, e.g., via plastic or elastic deformation.In a particular embodiment, a filler (not illustrated) can beincorporated within a void formed between at least one projection 7 andthe sidewall 4. That is, the filler can be positioned behind theprojection 7. The filler can include a stiffness adjustingcharacteristic. In such a manner, the projections 7 can be engineeredwith specific mechanical properties for particular applications. In yeta more particular embodiment, the filler can be sealed within the voidof the projection 7.

Referring particularly to FIG. 2C, in another embodiment, one of thefolded portions 5 a can include a projection 7. Similar to theembodiment illustrated in FIG. 2B, the folded portion 5 a can exhibitzero, or nominal, spring effect at locations not occupied by theprojection 7. In such a manner, the projection 7 can absorb toleranceand radial forces, e.g., via plastic or elastic deformation. The otherfolded portion 5 b can include a compression feature 6 having a springeffect. In such a manner, two axially or circumferentially adjacentfolded portions 5 a and 5 b can absorb tolerance and other mechanicalmisalignments via different mechanisms and properties.

Referring particularly to FIG. 2D, in a further embodiment, both of thefolded portions 5 can include a compression feature 6 and a projection 7having tolerance absorption properties. In such a manner, tolerance canbe absorbed by both the spring effect of the compression feature 6 anddeformation of the projection 7. A tolerance absorption ratio asmeasured by the relative tolerance compensation of the compressionfeatures 6 and the projections 7 can be engineered for particularapplications.

Referring particularly to FIG. 2E, in yet another embodiment, anunfolded portion of the sidewall 4 can include a projection 7 formedtherein. The projection 7 can be stamped, punched, rolled, or otherwiseshaped by a process as recognizable in the art to skilled artisans. Thefolded portion 5 can include a compression feature 6 having a springeffect. A skilled artisan will understand that several combinations ofthe embodiments described in FIGS. 2A to 2E can be generated. Moreover,in an embodiment, circumferentially adjacent folded portions of thetolerance ring 2 can each have different structures and arrangements,e.g., compression features and projections.

In accordance with one or more embodiments, the folded portions 5 canextend in a generally radial direction, e.g., radially inward toward thecentral axis 8 or radially outward away from the central axis 8. In sucha manner, the folded portions 5 can be shaped inwardly, outwardly, or acombination thereof. For example, in a particular embodiment, at leastone of the folded portions 5 can extend radially inward and at least oneother folded portion 5 can extend radially outward. In anotherembodiment, at least one of the folded portions 5 can extend bothradially inward and radially outward. More particularly, the foldedportion 5 can extend radially inward prior to extending radiallyoutward. In an embodiment, the folded portion 5 can form both an innerdiameter and an outer diameter of the tolerance ring 2.

In an embodiment, the folded portions 5 can exhibit zero, or nominal,spring effect at locations between adjacent compression features 6 andprojections 7. For example, as illustrated in FIGS. 1 and 3, theportions of the tolerance ring disposed between adjacent compressionfeatures 6 can include a flattened, double-wall construction, i.e., amajor surface 12 of the folded portion contacts the underlying majorsurface 12. In an embodiment, e.g., as illustrated in FIG. 9, theportions of the tolerance ring disposed between adjacent compressionfeatures 6 can include a single wall construction, i.e., a portion ofthe major surface 12 disposed between adjacent compression features 6 isexposed, e.g., the major surface 12 is exposed along the portion.

Prior to shaping, the sidewall 4 can initially comprise a strip ofmaterial 14. Referring now to FIGS. 4 and 5, the strip 14 can define a(first) major surface 10 and a (second) major surface 12. The majorsurfaces 10 and 12 can be spaced apart by a thickness, T, of the strip14. In an embodiment, prior to formation of the tolerance ring 2, themajor surfaces 10 and 12 can extend along generally parallel planes(FIG. 5). In a further embodiment, the strip 14 can have a uniformthickness as measured prior to shaping (FIG. 5).

In an embodiment, the strip 14 can define a first edge 16, a second edge18, a third edge 20, and a fourth edge 22. In a more particularembodiment, the first 16 and third edges 20 can be disposed at oppositesides of the strip 14, and the second 18 and fourth edges 22 can bedisposed at opposite sides of the strip 14. In another embodiment, thestrip 14 can define more or less than four edges. For example, the strip14 can define a triangle, a pentagon, a hexagon, a heptagon, an octagon,a nonagon, a decagon, or any other polygon having any number ofadditional edges.

In an embodiment, the strip 14 can have a polygonal shape. The first,second, third, and fourth edges 16, 18 20, and 22 can be disposed aroundthe strip 14 consecutively positioned in circumferential arrangement. Ina more particular embodiment, the strip 14 can have a generallyrectangular shape. In this regard, the first and third edges 16 and 20can be parallel and the second and fourth edges 18 and 22 can beparallel. Moreover, the first and third edges 16 and 20 can beperpendicular to the second and fourth edges 18 and 22.

In a particular embodiment, the strip 14 can include a substrate 50. Thesubstrate 50 can include, or essentially include, a metal or an alloy.More particularly, the substrate 50 can include, or essentially include,a steel. In yet a more particular embodiment, the substrate 50 caninclude, or essentially include, a medium- or high-carbon steel, suchas, for example, a spring steel. In an embodiment, the substrate 50 canhave a high yield strength, e.g., a yield strength of at least 200 MPa,such as at least 400 MPa, at least 600 MPa, at least 800 MPa, or even atleast 1000 MPa. In a further embodiment, the substrate 50 can have ayield strength of no greater than 10,000 MPa, such as no greater than5,000 MPa, or even no greater than 2,000 MPa.

In an embodiment, the strip 14 can further include, or essentiallyinclude, a polymeric layer 52. In an embodiment, the polymeric layer 52can include, or essentially include, a low friction material, e.g., amaterial having a coefficient of static friction of less than 0.5, suchas less than 0.4, less than 0.3, less than 0.2, less than 0.1 or evenless than 0.05 as measured dry against steel.

In a certain embodiment, the polymeric layer 52 can include, oressentially include, a low friction polymer, such as, a fluoropolymer,such as a polytetrafluoroethylene (PTFE). Other exemplary fluoropolymerscan include a fluorinated ethylene propylene (FEP), a polyvinylidenefluoride (PVDF), a perfluoroalkoxy (PFA), a terpolymer oftetrafluoroethylene, a hexafluoropropylene and vinylidene fluoride(THV), a polychlorotrifluoroethylene (PCTFE), an ethylenetetrafluoroethylene copolymer (ETFE), an ethylenechlorotrifluoroethylene copolymer (ECTFE), or any combination thereof.Additionally, it is possible to use a large number of other slidingmaterials, such as, for example, those marketed by Saint-Gobain underthe trademark Norglide®.

In yet a further embodiment, a lubricant can be disposed on, or within,the polymeric layer 52. Exemplary lubricants include molybdenumdisulfide, tungsten disulfide, graphite, grapheme, expanded graphite,boron nitrade, talc, calcium fluoride, or any combination thereof.Additionally, the lubricant can include alumina, silica, titaniumdioxide, calcium fluoride, boron nitride, mica, Wollastonite, siliconcarbide, silicon nitride, zirconia, carbon black, pigments, or anycombination thereof.

The polymeric layer 52 can be coupled to at least a portion of thesubstrate 50, for example, by an adhesive, mechanical anchoring, or as apressed or otherwise formed laminate. In a particular embodiment, thepolymeric layer 52 can extend along only one surface of the substrate50. In a non-illustrated embodiment, the polymeric layer 52 can fullyencapsulate the substrate 50.

Referring now to FIG. 6, during shaping, the first edge 16 of the strip14 can be shaped toward the third edge 20. For example, the strip 14 canbe folded, bent, or otherwise manipulated such that a distance betweenthe first and third edges 16 and 20 decreases at one or more locationsthere along to form the folded portion 5. In a particular embodiment,the first edge 16 can be uniformly shaped toward the third edge 20,i.e., the folded portion 5 has a uniform shape and size along a lengthof the first edge 16. Dashed outlines A, B, and C are intended to showexemplary conformation outlines of shapes through which the strip 14 maypass during the shaping process. A skilled artisan will recognize thatthe dashed outlines A, B, and C are merely illustrative and are notintended to limit the scope of the disclosure.

As illustrated by outline D, the first edge 16 can be shaped toward theunderlying sidewall 4. In an embodiment, the first edge 16 can be incontact with the underlying sidewall 4. In another embodiment, asillustrated, the first edge 16 can be spaced apart from the underlyingsidewall 4. A nominal distance between the first edge 16 and theunderlying sidewall 4 may be advantageous for initial toleranceabsorption as encountered during initial installation between an innerand outer component. The nominal distance may also increase relativeaxial sliding of the first edge 16 toward the third edge 20 during use.

In an embodiment, a preformed axial length, L_(PA), of the strip 14 canbe reduced by at least 5%, such as by at least 10%, at least 15%, atleast 20%, at least 25%, at least 30%, at least 35%, at least 40%, oreven at least 45% as the first edge 16 is shaped toward the third edge20 to form a new axial length, L_(N), of the strip 14. As used herein,“preformed axial length” refers to the axial length of the strip 14 asmeasured between the first and third edges 16 and 20 prior to shaping(e.g., FIGS. 4 and 5). More particularly, “preformed axial length” canrefer to the length between the first and third edges 16 and 20 prior toforming the folded portions 5 or any other features which reduce thedistance between the first and third edges 16 and 20. Even moreparticularly, “preformed axial length” may refer to a relative axiallength of the strip 14 as measured at each position along the first andthird edges. In strips having non-rectangular shapes the preformed axiallength may vary as measured from the second edge 18 to the fourth edge22. In this regard, the preformed axial length may be a function of thespecific location of measurement along the first and third edges 16 and20. In a further embodiment, the preformed axial length of the strip 14can be reduced during shaping of the first edge 16 to the third edge 20by no greater than 50%, such as by no greater than 49%, no greater than48%, no greater than 47%, or even by no greater than 46%.

In an embodiment, the strip 14 can be folded such that an internalangle, as measured between the sidewall and the folded portions 5 asformed by folding the first edge 16 toward the third edge 20, can be atleast 10°, at least 45°, or even at least 90°. In a further embodiment,the internal angle can be at least 100°, at least 135°, or even at least180°.

An axial apex formed during shaping of the first edge 16 toward thethird edge 20 can form a first axial end 26 of the tolerance ring 2.

In a particular embodiment, formation of the projections 7 can occurprior to shaping the first edge 16 toward the third edge 20. In such amanner, the projections 7 can be formed along a planar surface, e.g., bya press or a hammer. A skilled artisan will recognize that projectionsformed prior to shaping may be formed with a reverse orientation suchthat after shaping, the projections are oriented in the proper radialdirection. In another embodiment, formation of the projections 7 canoccur during or after shaping of the first edge 16 toward the third edge20. In such a manner, the projections 7 can be formed as the sidewall 4of the tolerance ring 2 approaches or reaches its final position. Thismay reduce or eliminate generation of stress risers within or adjacentto the projections 7 which may result in cracking during shaping of thefirst edge 16 toward the third edge 20.

In yet a further, non-illustrated embodiment, projections can be formedalong at least two circumferential rows. The rows of projections canextend in the same directions from the strip prior to shaping the strip.In such a manner, shaping of the first edge toward the third edge canform both inwardly and outwardly extending projections. In a moreparticular embodiment, shaping of the first edge toward the third edgecan align the inwardly and outward extending projections, i.e., theprojections are disposed at least substantially along the same axial andcircumferential positions.

In yet another, non-illustrated embodiment, the projections can beformed along at least two circumferential rows, where the projections ofeach row extend in opposite directions from the strip prior to shapingthe strip. The projections can have slightly offset size such that uponshaping of the first edge toward the third edge, the projections canradially overlap. In such a manner, the engineered strength of theprojections can be engineered for specific applications.

In an embodiment, after shaping the first edge 16 toward the third edge20, the second edge 18 of the strip 14 can be shaped toward the fourthedge 22 to define an annular sidewall 4 (FIG. 7). For example, the strip14 can be folded, bent, or otherwise manipulated such that a distancebetween the second and fourth edges 18 and 22 decreases. In this regard,the second and fourth edges 18 and 22 can define circumferential ends ofthe tolerance ring 2, forming a circumferential gap extending along theaxial length of the tolerance ring 2. The second and fourth edges 18 and22 can be brought together to further reduce the size of thecircumferential gap. In a particular embodiment, the second and fourthedges 18 and 22 can be coupled together. In a further embodiment, thesecond and fourth edges 18 and 22 can be joined, e.g., by welding, anadhesive, by a threaded or non-threaded fastener, by mechanicaldeformation such as crimping, or by any other suitable methodrecognizable in the art for joining circumferential gaps in tolerancerings.

In an embodiment, the tolerance ring 2 can have a multiple wallconstruction. As used herein, “multiple wall construction” refers to asidewall including an annular body shaped such that a line extendingradially outward from a central axis of the annular body intersects twoor more discrete annular sidewalls along at least one axial position ofthe central axis. In embodiments where the sidewall is formed from alaminate including, for example, a substrate and a low frictionmaterial, the laminate is considered as one discrete annular sidewall.The “multiple wall construction” can include three radially adjacentsidewalls, four radially adjacent sidewalls, five radially adjacentsidewalls, or even six radially adjacent sidewalls. In accordance withan embodiment, the “multiple wall construction” can include no greaterthan 100 radially adjacent sidewalls, such as no greater than 50radially adjacent sidewalls, or even no greater than 20 radiallyadjacent sidewalls. “Multiple wall construction” as used herein does notinclude a sidewall formed from a single piece of material concentricallylooped in a circumferential direction to form a multiple layer ring, butrather includes a material shaped in an axial direction. In anembodiment, the tolerance ring 2 can have a multiple wall constructionalong at least 25% of an axial length of the tolerance ring 2, such asalong at least 50% of the axial length, at least 60% of the axiallength, along at least 75% of the axial length, at least 80% of theaxial length, or even at least 85% of the axial length. In anotherembodiment, the tolerance ring can have a multiple wall constructionalong less than 100% of the axial length of the tolerance ring, such asno greater than 99% of the axial length, no greater than 98% of theaxial length, no greater than 97% of the axial length, no greater than96% of the axial length, no greater than 95% of the axial length, oreven no greater than 90% of the axial length.

In a more particular embodiment, illustrated in FIGS. 8 and 9, one ormore slots 24 can be formed in the strip 14. Dashed outline A (FIG. 8)is intended to show the strip 14 prior to shaping.

In an embodiment, at least one of the slots 24 can be formed in thestrip 14 prior to shaping the first edge 16 toward the third edge 20.The slots 24 can be formed along the first edge 16, the third edge 20,or along a combination thereof. At least one of the slots 24 can extendfrom the first or third edges 16 or 20 toward the third or first edges20 or 16, respectively. More particularly, all of the slots 24 canextend from the first or third edges 16 or 20 toward the third or firstedges 20 or 16. The slots 24 can facilitate shaping of the first edge 16toward the third edge 20, or the third edge 20 to the first edge 16(discussed in greater detail below). More particularly, the slots 24 canalleviate stress risers from forming within the strip 14 during theshaping processes. Additionally, the slots 24 can increase toleranceabsorption or even tolerance sensitivity, e.g., by allowing deflectionof the compression features 6 at lower radial loading conditions. Yetadditionally, the slots 24 can assist in shaping the second edge 18toward the fourth edge 22 of the strip 14.

In a particular embodiment, all of the slots 24 can be oriented in agenerally parallel direction. As used herein, a “generally paralleldirection” refers to an angular offset between two or more lines, orcentral lines in the case of non-straight lines (e.g., arcuate lines),of no greater than 15°, such as no greater than 10°, no greater than 5°,no greater than 2°, or even no greater than 1°. In a more particularembodiment, all of the slots 24 can be oriented in a parallel direction.As used herein, a “parallel direction” refers to an angular offsetbetween two or more lines, or central lines in the case of non-straightlines (e.g., arcuate lines), of no greater than 0.1°.

In yet another embodiment, the slots 24 can be oriented perpendicular,or generally perpendicular (e.g., between 75° and 105°, such as between85° and 95°), with respect to the first and third edges 16 and 20.

The slots 24 can have a length, L_(S), as measured by a shortestdistance from the first or third edge 16 or 20 to an axial end of theslot, e.g., a maximum distance from the first or third edge 16 or 20 toa furthest point of the slot 24, as measured in a directionperpendicular to the first or third edge 16 or 20. In an embodiment,L_(S) can be no greater than 50% of the preformed axial length of thestrip 14. In a further embodiment, L_(S) can be no greater than 45% ofthe preformed axial length, such as no greater than 40% of the preformedaxial length, no greater than 35% of the preformed axial length, nogreater than 30% of the preformed axial length, no greater than 25% ofthe preformed axial length, no greater than 20% of the preformed axiallength, no greater than 15% of the preformed axial length, no greaterthan 10% of the preformed axial length, or even no greater than 5% ofthe preformed axial length. In yet a further embodiment, L_(S) can be noless than 0.1% of the preformed axial length of the strip 14, such as noless than 0.5%, no less than 1%, no less than 2%, no less than 3%, oreven no less than 4%. In an embodiment, each slot 24 can terminate at astress concentration reducing element, e.g., a round or relief slot (notillustrated). The stress concentration reducing element may reduce thebuildup of stress risers within the strip 14 during shaping. This canreduce cracking or fracturing of the strip 14 during formation and use.

In a more particular embodiment, at least one slot 24 can be disposedbetween adjacent folded portions 5. More particularly, one slot 24 canbe disposed between each folded portion 5. The slots 24 may increaseindependent flexural response of each folded portion 5 to loadingconditions, thereby increasing concentricity capabilities of thetolerance ring 2.

In another embodiment, after shaping the first edge 16 of the strip 14toward to the third edge 20, but prior to shaping the second edge 18 ofthe strip 14 to the fourth edge 22, the third edge 20 of the strip 14can be shaped toward the first edge 16. For example, the strip 14 can befolded, bent, or otherwise manipulated such that a distance between thefirst and third edges 16 and 20 further decreases at one or morelocations along the strip of material 14 (FIG. 2). In an embodiment, thestrip 14 can have an axial length after folding the first edge 16 towardthe third edge 20 that is further reduced by at least 5%, such as by atleast 10%, at least 15%, at least 20%, at least 25%, at least 30%, atleast 35%, at least 40%, or even at least 45%, upon shaping the thirdedge 20 toward the first edge 16. The edge formed by this process canform a second axial end 28 of the tolerance ring 2. Moreover, twocircumferentially extending rows of folded portions 5 can be formed,each at, or immediately adjacent to, an axial end 26 or 28 of thetolerance ring 2.

As discussed above, one or more slots 24 can be formed in the strip 14along the third edge 20. In an embodiment, at least one of the slots 24can be formed in the strip 14 prior to shaping the third edge 20 towardthe first edge 16. The slots 24 can be formed along the third edge 20.At least one of the slots 24 can extend from the third edge 20 towardthe first edge 16. More particularly, all of the slots 24 can extendfrom the third edge 20 toward the first edge 16. The slots 24 canfacilitate shaping of the third edge 20 to the first edge 16. Moreparticularly, the slots 24 can alleviate stress risers from formingwithin the strip 14 during the shaping processes. Additionally, theslots 24 can increase tolerance absorption or even tolerancesensitivity, e.g., by allowing deflection of the compression features 6at lower radial loading conditions.

The slots 24 formed along the third edge 20 can have any number ofsimilar features as the slots 24 formed along the first edge 16. Forexample, the slots 24 along the third edge 20 may be oriented in agenerally parallel, or parallel, direction with one another. In anotherembodiment, the slots 24 along the third edge 20 can be orientedperpendicular, or generally perpendicular (e.g., between 75° and 105°,such as between 85° and 95°), with respect to the first and third edges16 and 20. In yet another embodiment, the slots can have a length,L_(S), as measured by a shortest distance from the third edge 20 to anaxial end of the slot 24. In an embodiment, L_(S) can be no greater than50% of the preformed axial length of the strip 14. In a furtherembodiment, L_(S) can be no greater than 45% of the preformed axiallength, such as no greater than 40% of the preformed axial length, nogreater than 35% of the preformed axial length, no greater than 30% ofthe preformed axial length, no greater than 25% of the preformed axiallength, no greater than 20% of the preformed axial length, no greaterthan 15% of the preformed axial length, no greater than 10% of thepreformed axial length, or even no greater than 5% of the preformedaxial length. In yet a further embodiment, L_(S) can be no less than0.1% of the preformed axial length of the strip 14, such as no less than0.5%, no less than 1%, no less than 2%, no less than 3%, or even no lessthan 4%. In yet a further embodiment, each slot 24 can terminate at astress concentration reducing element, e.g., a round or relief slot (notillustrated). The stress concentration reducing element may reduce thebuildup of stress risers within the strip 14 during shaping. This canreduce cracking or fracturing of the strip 14 during formation and use.

In accordance with an embodiment, in order to increase stability andresistance of the tolerance ring 2 to deformation, torqueing, andtwisting, at least three compression features 6 or projections 7 can bedisposed along each opposite axial end 26 and 28 of the tolerance ring2. The three compression features 6 or projections 7 along each axialend 26 and 28 can form a total of six points of radial contact with oneof the inner and outer components (not illustrated).

In an embodiment, the compression features 6 or projections 7 can beequally spaced apart in a circumferential direction.

Referring now to FIG. 10, in an embodiment, the tolerance ring 2 canfurther include a rib 30 extending at least partially around thecircumference of the sidewall 4. More particularly, the rib 30 canextend circumferentially around the entire sidewall 4. The rib 30 can bedisposed at a central location of the tolerance ring 2. Moreparticularly, the rib 30 can be disposed at an axially central locationof the tolerance ring 2.

In a particular embodiment, the rib 30 can be unitary, e.g., monolithic,with the sidewall 4 of the tolerance ring 2. The rib 30 can be shaped bybending, folding, or otherwise similarly manipulating the sidewall 4. Inan embodiment, the rib 30 can have a projected radial height 32 asmeasured perpendicular to the major surface 12, that is at least 25% ofthe thickness, T, of the sidewall 4. In a further embodiment, theprojected radial height 32 can be at least 50% T, such as at least 75%T, at least 100% T, at least 125% T, at least 150% T, at least 175% T,or even at least 200% T. In another embodiment, the projected radialheight 32 can be no greater than 10,00% T, such as no greater than5,000% T, no greater than 1,000% T, no greater than 900% T, no greaterthan 800% T, no greater than 700% T, no greater than 600% T, or even nogreater than 500% T.

In an embodiment, the rib 30 can have an axial length 34, as measuredalong the major surface 12, that is less than 25% of a formed axiallength of the tolerance ring 2. As used herein, “formed axial length” isthe axial length of the tolerance ring as measured after shaping isfinished, e.g., after forming the folded portions 5, the rib 30, and anyother features which change the axial length of the tolerance ring. In afurther embodiment, the rib 30 can have an axial length 34 that is lessthan 20% the formed axial length of the tolerance ring, such as lessthan 15% the formed axial length of the tolerance ring, less than 10%the formed axial length of the tolerance ring, or even less than 5% theformed axial length of the tolerance ring. In another embodiment, therib 30 can have an axial length 34 that is at least 0.1% the formedaxial length of the tolerance ring, such as at least 0.5% the formedaxial length of the tolerance ring, at least 1% the formed axial lengthof the tolerance ring, at least 2% the formed axial length of thetolerance ring, at least 3% the formed axial length of the tolerancering, or even at least 4% the formed axial length of the tolerance ring.

In an embodiment, the folded portions 5 can freely float, e.g., aftershaping they are not secured to major surface 12, but instead cantranslate along the major surface 12. The rib 30 can form an axial stop,preventing the folded portions 5 from translating beyond a prescribedposition along the axial length of the tolerance ring 2.

In an embodiment, the rib 30 can have a generally frustoconical shape,defining two walls 36 and 38. More particularly, the walls 36 and 38 candefine a relative base angle 40 that is at least 45°, such as at least60°, at least 75°, at least 90°, at least 105°, or even at least 120°.In yet a more particular embodiment, the relative base angle 40 can beno greater than 179°, such as no greater than 175°, no greater than160°, no greater than 145°, or even no greater than 130°. For relativebase angles 40 of less than 90° the walls 36 and 38 of the rib 30 canform an immediate stop, preventing the compression features 6 fromfurther translating. For relative base angles 40 of greater than 90°,the walls 36 and 38 of the rib 30 can form a wedge, increasing the forcenecessary for continued translation of the compression feature 6.

In another embodiment, the rib 30 can increase a stiffness of thetolerance ring by at least 1% as compared to a similar tolerance ringdevoid of a rib 30. As used herein, “stiffness of the tolerance ring”refers to a relative ability of the tolerance ring to avoid deformationas caused, for example, by torsional or rotational forces. For example,if an identical force is applied to two tolerance rings at the samerelative locations, and the first tolerance ring deflects 5 mm while thesecond tolerance ring deflects 10 mm, the first tolerance ring has astiffness of 200% the stiffness of the second tolerance ring. In afurther embodiment, the rib 30 can increase the stiffness of thetolerance ring 2 by at least 2% as compared to a similar tolerance ringdevoid of a rib 30, such as by at least 3%, at least 4%, at least 5%, atleast 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least15%, at least 20%, at least 25%, at least 30%, at least 35%, at least40%, at least 45%, at least 50%, at least 75%, at least 100%, at least150%, at least 200%, or even at least 500%. In another embodiment, therib 30 can increase the stiffness of the tolerance ring 2 by no greaterthan 1000%, such as no greater than 750%.

Referring now to FIG. 11, an assembly 100 can comprise a tolerance ring2 disposed within an annular gap 106 formed between in inner component,e.g., a shaft, 102 and an outer component, e.g., a bore, 104. A skilledartisan will recognize that the folded portions 5 can be orientedradially outward (as illustrated) or radially inward depending on theapplication.

In an embodiment, at least a portion of the folded portions 5 cantranslate generally along lines 42 and 44 toward the rib 30 as a radialloading force is applied to the outermost portions of the tolerance ring2. Additionally, the folded portions 5 can further compress in a radialdirection, as illustrated by lines 46 and 48. In this regard, the foldedportions 5 can absorb radial loading forces between the inner and outercomponents 102 and 104.

In a particular embodiment, the assembly 100 can comprise a portion of ahard disk drive (HDD). For example, the inner component 102 can be apivot, the outer component 104 can be an actuator arm, and the tolerancering 2 can provide torque transmission therebetween. However, theassembly 100 is not intended to be limited to HDD assemblies. Forexample, the assembly 100 can be used in the automotive and aerospaceindustries, the energy sector, as well as in various machinery andindustries that require the use of a torque transmitter. Furtherexemplary applications include steering columns, stators, compressors,stanchions, axles, and other similar reciprocating and rotatingassemblies.

In an embodiment, the folded portions 5 can be disposed at, orimmediately adjacent to, opposite axial ends of the tolerance ring 2.Traditional tolerance rings typically have either: (1) projectionsspaced apart from the axial ends of the ring to increase uniformityacross the axial length of the projections, or (2) corrugationsextending along the entire axial length of the tolerance ring. Suchfeatures reduce stabilizing capacity of the tolerance rings againsttorsional forces, circumferential forces, axial forces, and combinationsthereof. Utilization of folded portions 5 along, or at, axial ends ofthe tolerance ring 2 can increase stabilizing capacity and reduce wobbleby spacing the circumferentially extending rows of projections apartfrom one another to a maximum extent permitted by the axial length ofthe tolerance ring.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described below. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are illustrative and do not limit the scope of the presentinvention. Embodiments may be in accordance with any one or more of theitems as listed below.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described below. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the embodiments as listed below.

Embodiment 1

A tolerance ring comprising:

-   -   a sidewall having a first and a second opposite major surfaces        spaced apart by a thickness, wherein the first major surface        defines an inner diameter of the tolerance ring at a first        location of the sidewall and an outer diameter of the tolerance        ring at a second location of the sidewall.

Embodiment 2

The tolerance ring according to the preceding embodiment, wherein thetolerance ring comprises a multiple wall construction along at least 25%of an axial length of the tolerance ring, such as along at least 50% ofthe axial length, at least 60% of the axial length, along at least 75%of the axial length, at least 80% of the axial length, or even at least85% of the axial length.

Embodiment 3

The tolerance ring according to any one of the preceding embodiments,wherein the first major surface defines a radially outermost surface ofthe tolerance ring at a first location of the sidewall and a radiallyinnermost surface of the tolerance ring at a second location of thesidewall.

Embodiment 4

A tolerance ring having a multiple wall construction along at least 25%of an axial length of the tolerance ring, such as along at least 50% ofthe axial length, at least 60% of the axial length, along at least 75%of the axial length, at least 80% of the axial length, or even at least85% of the axial length.

Embodiment 5

The tolerance ring according to any one of the preceding embodiments,wherein the multiple wall construction extends along less than 100% ofthe axial length of the tolerance ring, such as no greater than 99% ofthe axial length, no greater than 98% of the axial length, no greaterthan 97% of the axial length, no greater than 96% of the axial length,no greater than 95% of the axial length, or even no greater than 90% ofthe axial length.

Embodiment 6

The tolerance ring according to any one of embodiments 4 and 5, whereinthe multiple wall construction comprises 2 sidewalls.

Embodiment 7

The tolerance ring according to any one of embodiments 4-6, wherein themultiple wall construction comprises at least 3 sidewalls, such as atleast 4 sidewalls, or even at least 5 sidewalls.

Embodiment 8

The tolerance ring according to any one of embodiments 4-7, wherein themultiple wall construction comprises no greater than 100 sidewalls, suchas no greater than 50 sidewalls, or even no greater than 20 sidewalls.

Embodiment 9

The tolerance ring according to any one of the preceding embodiments,wherein the sidewall comprises a metal.

Embodiment 10

The tolerance ring according to any one of the preceding embodiments,wherein the sidewall comprises a steel, such as spring steel.

Embodiment 11

The tolerance ring according to any one of the preceding embodiments,wherein the tolerance ring further comprises a polymeric layer, andwherein the polymeric layer is coupled to at least a portion of thesidewall.

Embodiment 12

The tolerance ring according to embodiment 11, wherein the polymericlayer comprises a low friction material.

Embodiment 13

The tolerance ring according to any one of embodiments 11 and 12,wherein the polymeric material comprises a PTFE.

Embodiment 14

The tolerance ring according to any one of the preceding embodiments,wherein the tolerance ring comprises a plurality of folded portions.

Embodiment 15

The tolerance ring according to embodiment 14, wherein the foldedportions comprise compression features

Embodiment 16

The tolerance ring according to embodiment 15, wherein the compressionfeatures are adapted to absorb a tolerance between an inner componentand an outer component.

Embodiment 17

The tolerance ring according to any one of embodiments 15 and 16,wherein the compression features are disposed adjacent to an axial endof the tolerance ring.

Embodiment 18

The tolerance ring according to any one of embodiments 15-17, whereinthe tolerance ring has a first and second opposite axial ends, andwherein at least three compression features are disposed at the firstaxial end and at least three compression features are disposed at thesecond axial end.

Embodiment 19

The tolerance ring according to any one of embodiments 15-18, whereinthe compression features are equally spaced apart in a circumferentialdirection around the tolerance ring.

Embodiment 20

The tolerance ring according to any one of embodiments 15-19, whereinthe compression features are folded.

Embodiment 21

The tolerance ring according to any one of embodiments 14-20, whereinthe folded portions comprise radially extending projections.

Embodiment 22

The tolerance ring according to any one of embodiments 14-20, whereinthe folded portions are continuous with a sidewall of the tolerancering.

Embodiment 23

The tolerance ring according to any one of embodiments 14-21, whereinthe folded portions are unitary with a sidewall of the tolerance ring.

Embodiment 24

The tolerance ring according to any one of embodiments 15-22, whereinthe tolerance ring has a sidewall defining a thickness, and wherein thecompression features have a projected radial height greater than thethickness of the sidewall.

Embodiment 25

The tolerance ring according to embodiment 24, wherein the projectedradial height of the compression features is at least 110% the thicknessof the sidewall, such as at least 115%, at least 120%, at least 125%, atleast 130%, at least 135%, at least 140%, at least 145%, at least 150%,at least 175%, at least 200%, at least 225%, at least 250%, at least275%, at least 300%, or even at least 500%.

Embodiment 26

The tolerance ring according to any one of embodiments 24 and 25,wherein the projected radial height of the compression features is nogreater than 1,000% the thickness of the sidewall, such as no greaterthan 900%, no greater than 800%, or even no greater than 700%.

Embodiment 27

The tolerance ring according to any one of embodiments 15-26, whereinthe compression features are deformable in an axial direction.

Embodiment 28

The tolerance ring according to any one of embodiments 15-27, wherein atleast a portion of at least one of the compression features is adaptedto translate in an axial direction upon receipt of a radial loadingcondition.

Embodiment 29

The tolerance ring according to any one of embodiments 15-28, whereinall of the compression features are adapted to translate in an axialdirection upon receipt of a radial loading condition.

Embodiment 30

The tolerance ring according to any one of embodiments 28 and 29,wherein translation of the compression feature occurs in a directiontoward an opposite axial end of the tolerance ring from which thecompression feature extends.

Embodiment 31

The tolerance ring according to any one of the preceding embodiments,wherein the tolerance further comprises a rib extendingcircumferentially around the tolerance ring.

Embodiment 32

The tolerance ring according to embodiment 31, wherein the rib isunitary with a sidewall of the tolerance ring.

Embodiment 33

The tolerance ring according to any one of embodiments 31 and 32,wherein the rib extends around the tolerance ring at an axially centrallocation.

Embodiment 34

The tolerance ring according to any one of embodiments 31-33, whereinthe rib has a projected radial height that is at least 25% the thicknessof a sidewall of the tolerance ring, such as at least 50%, at least 75%,or even at least 100%.

Embodiment 35

The tolerance ring according to any one of embodiments 31-34, whereinthe rib has a projected radial height that is no greater than 1000% thethickness of the sidewall, such as no greater than 900%, no greater than800%, or even no greater than 700%.

Embodiment 36

The tolerance ring according to any one of embodiments 31-35, whereinthe rib has an axial length that is less than 25% of a formed axiallength of the tolerance ring, such as less than 20%, less than 15%, lessthan 10%, or even less than 5%.

Embodiment 37

The tolerance ring according to any one of embodiments 31-36, whereinthe rib has an axial length that is at least 0.1% of a formed axiallength of the tolerance ring, such as at least 0.5%, at least 1%, atleast 2%, at least 3%, or even at least 4%.

Embodiment 38

The tolerance ring according to any one of embodiments 31-37, whereinthe rib forms an axial stop, the axial stop preventing a compressionfeature from translating beyond the rib.

Embodiment 39

The tolerance ring according to any one of embodiments 31-38, whereinthe rib increases a stiffness of the tolerance ring at least 1% ascompared to a similar tolerance ring devoid of a rib, such as anincrease of at least 2%, an increase of at least 3%, an increase of atleast 4%, or even an increase of at least 5%.

Embodiment 40

The tolerance ring according to any one of the preceding embodiments,wherein the tolerance ring comprises a preformed axial length, L_(PA),wherein the tolerance ring comprises a formed axial length, L_(N), andwherein L_(N) is less than 95% L_(P), such as less than 90% L_(P), lessthan 85% L_(P), less than 80% L_(P), less than 75% L_(P), less than 70%L_(P), less than 65% L_(P), less than 60% L_(P), or even less than 55%L_(P).

Embodiment 41

The tolerance ring according to embodiment 40, wherein L_(N) is at least5% L_(P), such as at least 10% L_(P), at least 15% L_(P), at least 20%L_(P), at least 25% L_(P), at least 30% L_(P), at least 35% L_(P), atleast 40% L_(P), or even at least 45% L_(P).

Embodiment 42

The tolerance ring according to any one of the preceding embodiments,wherein the tolerance ring comprises a formed axial length, and whereinthe entire formed axial length is adapted to be disposed within a bore.

Embodiment 43

An assembly comprising:

-   -   an outer component defining a bore;    -   an inner component disposed in the bore; and    -   a tolerance ring in accordance with any one of the preceding        embodiments, the tolerance ring disposed between the inner and        outer components.

Embodiment 44

A method of forming a tolerance ring comprising:

-   -   providing a strip of material comprising a first, a second, a        third, and a fourth edge;    -   shaping the first edge of the strip toward the third edge;    -   shaping the second edge of the strip toward the fourth edge.

Embodiment 45

The method according to embodiment 44, wherein shaping the first edgetoward the third edge forms a compression feature.

Embodiment 46

The method according to any one of embodiments 44 and 45, furthercomprising:

-   -   forming slots within the strip of material along the first and        third edges.

Embodiment 47

The method according to embodiment 46, wherein the step of forming slotsis performed before shaping the first edge toward the third edge.

Embodiment 48

The method according to any one of embodiments 46 and 47, wherein theslots extend from the first and third edges toward the third and firstedges, respectively.

Embodiment 49

The method according to any one of embodiments 46-48, wherein the slotsare oriented in a parallel direction.

Embodiment 50

The method according to any one of embodiments 46-49, wherein the slotsare oriented perpendicular to the first and third edges.

Embodiment 51

The method according to any one of embodiments 46-50, wherein the slotshave a length, and wherein the length of the slots is no greater than50% of a preformed axial length of the strip of material, such as nogreater than 45%, no greater than 40%, no greater than 35%, no greaterthan 30%, no greater than 25%, no greater than 20%, no greater than 15%,no greater than 10%, or even no greater than 5%.

Embodiment 52

The method according to any one of embodiments 46-51, wherein at leastone slot is formed between adjacent compression features.

Embodiment 53

The method according to any one of embodiments 44-52, wherein the stepof shaping the first edge toward the third edge forms a first axial endof the tolerance ring.

Embodiment 54

The method according to any one of embodiments 44-53, wherein the stepof shaping the first edge toward the third edge is performed by folding.

Embodiment 55

The method according to any one of embodiments 44-54, wherein the stripof material has a preformed axial length, and wherein the step ofshaping the first edge toward the third edge is performed such that thepreformed axial length of the strip of material is reduced by at least5%, such as at least 10%, at least 15%, at least 20%, at least 25%, atleast 30%, at least 35%, at least 40%, or even at least 45%.

Embodiment 56

The method according to any one of embodiments 44-55, furthercomprising:

-   -   shaping the third edge of the strip toward the first edge of the        strip.

Embodiment 57

The method according to embodiment 56, wherein the step of shaping thethird edge toward the first edge forms a second axial end of thetolerance ring.

Embodiment 58

The method according to any one of embodiments 56 and 76, wherein thestep of shaping the third edge toward the first edge is performed byfolding.

Embodiment 59

The method according to any one of embodiments 55-57, wherein the stripof material has an axial length after folding the first edge toward thethird edge, and wherein the step of shaping the third edge toward thefirst edge is performed such the preformed axial length is furtherreduced by at least 5%, such as at least 10%, at least 15%, at least20%, at least 25%, at least 30%, at least 35%, at least 40%, or even atleast 45%.

Embodiment 60

The method according to any one of embodiments 44-59, wherein the stepof shaping the second edge toward the fourth edge forms acircumferential end of the tolerance ring.

Embodiment 61

The method according to any one of embodiments 44-60, wherein the stepof shaping the second edge toward the fourth edge is performed byfolding.

Embodiment 62

The method according to any one of embodiments 44-61, wherein the stepof shaping the first edge of the strip toward the third edge isperformed before shaping the second edge of the strip toward the fourthedge.

Embodiment 63

The method according to any one of embodiments 44-62, furthercomprising:

-   -   coupling the second and fourth edges of the strip together.

Embodiment 64

The method according to any one of embodiments 44-63, furthercomprising:

-   -   welding the second edge of the strip to the fourth edge.

Embodiment 65

The method according to any one of embodiments 44-64, wherein the stripof material comprises a substrate, such as a metal, such as a springsteel.

Embodiment 66

The method according to any one of embodiments 44-65, wherein the stripof material further comprises a polymeric layer, such as afluoropolymer, such as PTFE.

Note that not all of the features described above are required, that aportion of a specific feature may not be required, and that one or morefeatures may be provided in addition to those described. Still further,the order in which features are described is not necessarily the orderin which the features are installed.

Certain features are, for clarity, described herein in the context ofseparate embodiments, may also be provided in combination in a singleembodiment. Conversely, various features that are, for brevity,described in the context of a single embodiment, may also be providedseparately or in any subcombinations.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments, However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

The specification and illustrations of the embodiments described hereinare intended to provide a general understanding of the structure of thevarious embodiments. The specification and illustrations are notintended to serve as an exhaustive and comprehensive description of allof the elements and features of apparatus and systems that use thestructures or methods described herein. Separate embodiments may also beprovided in combination in a single embodiment, and conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges includes each and everyvalue within that range. Many other embodiments may be apparent toskilled artisans only after reading this specification. Otherembodiments may be used and derived from the disclosure, such that astructural substitution, logical substitution, or any change may be madewithout departing from the scope of the disclosure. Accordingly, thedisclosure is to be regarded as illustrative rather than restrictive.

What is claimed is:
 1. A tolerance ring comprising: a sidewall having afirst and a second opposite major surfaces spaced apart by a thickness,wherein the first major surface defines an inner diameter of thetolerance ring at a first location of the sidewall and an outer diameterof the tolerance ring at a second location of the sidewall.
 2. Thetolerance ring according to claim 1, wherein the tolerance ringcomprises a multiple wall construction along at least 25% of an axiallength of the tolerance ring.
 3. The tolerance ring according to claim1, wherein a tangent to the first major surface at the second locationis parallel to a central axis of the tolerance ring.
 4. The tolerancering according to claim 1, wherein the tolerance ring further comprisesa low friction material coupled to at least a portion of the sidewall.5. The tolerance ring according to claim 1, wherein the tolerance ringcomprises at least one folded portion, and wherein at least one of theat least one folded portions comprises a compression feature adapted todeform in an axial direction.
 6. The tolerance ring according to claim5, wherein the compression feature is disposed adjacent to an axial endof the tolerance ring.
 7. The tolerance ring according to claim 1,wherein the tolerance ring comprises at least one folded portion, andwherein at least one of the at least one folded portions comprises aradially extending projection.
 8. The tolerance ring according to claim1, wherein the tolerance further comprises a rib extendingcircumferentially around the tolerance ring at an axially centrallocation.
 9. A tolerance ring having a multiple wall construction alongat least 25% of an axial length of the tolerance ring.
 10. The tolerancering according to claim 9, wherein the tolerance ring further comprisesa low friction material coupled to at least a portion of the sidewall.11. The tolerance ring according to claim 9, wherein the tolerance ringcomprises a folded portion, and wherein the folded portion comprises acompression feature disposed adjacent to an axial end of the tolerancering.
 12. The tolerance ring according to claim 11, wherein thecompression feature is deformable in an axial direction.
 13. Thetolerance ring according to claim 9, wherein the tolerance furthercomprises a rib extending circumferentially around the tolerance ring.14. The tolerance ring according to claim 13, wherein the rib extendsaround the tolerance ring at an axially central location.
 15. A methodof forming a tolerance ring comprising: providing a strip of materialcomprising a first, a second, a third, and a fourth edge; shaping thefirst edge of the strip toward the third edge; and shaping the secondedge of the strip toward the fourth edge.
 16. The method according toclaim 15, wherein shaping the first edge toward the third edge forms acompression feature.
 17. The method according to claim 15, furthercomprising: forming slots within the strip of material along at leastone of the first and third edges before shaping the first edge towardthe third edge.
 18. The method according to claim 15, wherein the stripof material has a preformed axial length, and wherein the step ofshaping the first edge toward the third edge is performed such that thepreformed axial length of the strip of material is reduced by at least25%.
 19. The method according to claim 15, further comprising: shapingthe third edge of the strip toward the first edge of the strip.
 20. Themethod according to claim 15, wherein the strip of material comprises asubstrate and a low friction layer.